Candidate of Science N. L. Batseva, student A. Kradetskaya

Tomsk Polytechnic University, Russia

The analysis of long-term steady states of Khakassia power system

Abstract

This report provides the general analysis of 500/220 kV electrical networks of the “Regional Dispatch Administration of Khakass power system” and also it is based on calculated of steady-states regimes including taking into account future development.

Keywords: Khakass power system, Sayano-Shushenskaya hydroelectric power station, transmission line, steady-states regimes.

I. Introduction.

The Republic of Khakassia is located in the southwestern part of the Eastern Siberia within the Sayano-Altaic mountain system. In the north and east Khakassia boarders with Krasnoyarsk Krai and in the west – with Kemerovo Oblast.

The “Regional Dispatch Administration of Khakassia power system” situates directly on the territory of Khakassia Republic and managers and supervises generating objects with total install capacity of 7038 MW. The electric power sector of Khakassia also includes 8, 33 and 47 overhead lines working at voltage of 500, 220 and 110 kV correspondingly. Total capacity of transformers installed in substations is 19355 MVA.

In the Republic of Khakassia the primary consumers are built on fabricators of various industries. For the most part of Electrical energy users are heavy engineering, coal mining, agribusiness, food industry companies and also residential customers.

II. Statement of the problem.

The Republic of Khakassia is the key power system in the aspect of electrical energy generation from Sayano-Shushenskaya hydroelectric power station and load peaks compensation on large territory of Siberian Federal District. In the east it is adjacent to Krasnoyarsk power system and in the west – to Kuzbass. High voltage lines working at 500 and 220 kV are the main inter-system links of republic with the other energy system.

Power system of Khakassia consists of the following main objects of generation:

- Sayano-Shushenskaya hydroelectric power station (the most powerful station in Russia with installed capacity of 6400 MW);

- Mainskaya hydroelectric power station with installed capacity of 321 MW;

- Abakan thermal power station with installed capacity of 270 MW and also two power stations (“Abaza-Energo” Ltd and “Sora” Ltd) with total installed capacity of 25 MW.

Sayano-Shushenskaya hydroelectric power station is the most powerful electric energy source within the Russian and Siberian United Energy System that covers seasonal and daily power deviations. The output of Sayano-Shushenskaya hydroelectric power station provides the consumers of Khakassia with required electrical energy and power via 500 kV transmission line Sayano-Shushenskaya – Oznachennoye – Abakan, and also it is a source of electrical energy for the western deficient power systems via 500 kV transmission line Sayano-Shushenskaya – Novokuznetsk.

Prior to the well-known incident Sayano-Shushenskaya hydroelectric power station generated jointly with Mainskaya hydroelectric power station 20-26 billion kilowatt hours (kWh) of electricity per a year and their output was approximately 4610 MW of power [1]. In winter it covered up to 5-15% of energy consumption over Siberia; a lack of capacity from this station produces a power deficit about 70 million kWh per a day.

Mainskaya hydroelectric power station is the control compensating power station that smoothes water level fluctuations in the river Yenisei which come from changing of operational modes in Sayano-Shushenskaya hydroelectric power station.

Abakan thermal power station is the main and the most important source of heat supply in the Republic of Khakassia. Energy output within the power system of Khakassia and connection with it is implemented via transmission lines working at voltage of 110 and 220 kV. Transmission is realized with the help of 200 MVA autotransformer by the 220 kV line Abakan-Rayonnaya substation – Abakan thermal power station, and through the 110 kV electrical networks to Abakan-Rayonnaya substation.

Transmission lines working at voltage of 500 kV provide the power transfer both supplying the Republic of Khakassia itself and carrying power flows between Khakass and Krasnoyarsk power systems. According to this stability of the Siberian United Energy System depends on reliability of these lines.

After the incident at Sayano-Shushenskaya hydroelectric power station energy consumption of Khakassia was dramatically higher in a comparison with the value of generation. This resulted in a disturbance both in Khakass and adjacent power systems.

III. Problem solution and results.

In this regard a number of measures aimed to improve system sustainability and stability in emergency situations was put forward.

First of all, it is planned to install the fourth turbine generator at Abakan thermal power station to cover the electrical loads growth in the zone of its proximate influence. Secondly, it is worked out a project of building the second circuit of the 500 kV transmission line Aluminievaya substation – Abakan substation– Itatskaya substation in order to improve reliability of existing line.

Figure 1 shows the scheme of Khakass power system including 500/220 kV networks.

Calculations of regimes were made with the help of the special software “MUSTANG”. Substations junction nodes of 110 kV were taken into account as loads, network reduction was not made in order to achieve more reliable values of intra- and inter-system power flows.

The results of calculations for existing and advanced schemes are presented in Tables 1 and 2. It is important to mention that these results were obtained considering reactor conductivities in calculations in order to prevent voltage reduction and keep its level according to required values. There were installed two groups of single-phase reactors on the buses of Abakan and Sora substations. This control measure helped to supply the necessary voltage level directly in these substations and also in the zone of Tuim substation taps.

Figure 1 – The scheme of 500/220 kV electrical networks of Khakassia before reconstruction

Table 1 – Node calculations

The name of substation	Designed voltage, kV (existing scheme)	Designed voltage, kV (advanced schemes)
Sayano-Shushenskaya hydroelectric power station 10 кV	15,75	15,75
Sayano-Shushenskaya hydroelectric power station 500 kV	513,90	518,70
Oznachennoye 500 kV	512,81	519,10
Aluminievaya 500 kV	510,33	513,99
Abakan 500 kV	500 (swing-bus)	500 (swing-bus)
Abakan-Rayonnaya 220 kV	241,59	200,63
Abakan thermal power station 220 kV	240,73	199,58

Table 2 – Branch calculations

The name of transmission line	Designed current, kA	Permissible current, kA	The scheme condition
Sayano-Shushenskaya – Oznachennoye 500 kV	0,63	0,945	existing scheme
Aluminievaya – Abakan 500 kV	1,47	0,825
Abakan thermal power station – Abakan-Rayonnaya 500 kV	0,34	0,825
Sayano-Shushenskaya – Oznachennoye 500 kV	0,63	0,945	advanced schemes
Aluminievaya – Abakan 500 kV (the first circuit)	0,8	0,825
Aluminievaya – Abakan 500 kV (the second circuit)	0,67	0,825
Abakan thermal power station – Abakan-Rayonnaya 500 kV	0,59	0,825

IV. Summary.

Analyzing the results there can be done the following conclusions:

1. Currently the existing 500 kV overhead line Aluminievaya substation – Abakan substation – Itatskaya substation is extremely unreliable [2]; the smallest system failures or emergency outage of this line will result in disturbance of both intra- and inter-system energy transfer separating Khakass and Krasnoyarsk power systems. Therefore construction of the second circuit will have a positive effect redistributing existing power flows.

2. It should be mentioned that Khakass power system has quite enough potential to add new generating capacities.

References

1. Khakass power engineering before and after breakdown // Power engineering. – 2010, № 32. – P. 10-19.

2. Reference document of electrical networks designing / edited by D.L. Faibisovich. – Moskow: Publishing house “ENAS”, 2006 – 320 p.